The present invention relates to a liquid crystal display video projector to enlarge and project the images of liquid crystal panels or like panels, and more particularly, to a liquid crystal panel or polarizing plate mounting structure and a method of repairing same.
Hitherto, there has been a device using a light source such as a metal halide lamp to enlarge and project the images of liquid crystal panels. In such conventional device, the light emitted from a light source is converged on a liquid crystal panel through a mirror or the like, and the image of the crystal liquid panel is projected on a screen through a projecting lens.
Recently, there is available a high luminance liquid crystal projector capable of projecting images on a large screen even in a bright room. For example, a light of 3000ANSI lumen can be emitted by using a liquid crystal panel of 1.3 inches in size. Also available is a micro-size projector using a small liquid crystal panel of B5 size such as 0.9 inch and 0.7 inch types.
As a method of mounting a liquid crystal panel on a liquid crystal display video projector, there is a proposal as described in the following. FIG. 6 is a perspective view of the essential parts of a conventional liquid projector. In FIG. 6, X prism 52 is located at the center of an optical portion for color synthesis. Three liquid crystal panels 50, and polarizing plate 51 disposed on each of the entrance and exit sides of respective liquid crystal panels 50 is secured on the three sides of X prism 52 by using adhesive 54 or screws via brackets 53 or the like in three directions. After that, the assembly of these parts is installed on an aluminum die-cast optical base 55. Further, a projecting lens 56 is secured on the wall of optical base 55 perpendicularly with respect to the X prism 52. After that, a fan 57 to cool the liquid crystal panel and a branch duct 58 to guide the air are assembled.
In such prior art liquid crystal display video projector, when three sheets of liquid crystal panel 50 are secured on the X prism unit, the green (G) liquid crystal panel located in the middle thereof is first secured at a predetermined position where the image comes to a focus in all directions in a generally parallel arrangement with the projecting lens. After that, the adjustment of convergence is made for the red (R) liquid crystal panel and the blue (B) liquid crystal panel before securing the panels. The projecting lens and the liquid crystal panel are individually retained by the optical base. Accordingly, the optical base will strain due to vibrations or shocks given if it falls during transportation, and as a result, there arises a problem of convergence deviation of the liquid crystal panels. Also, in such configuration, since the projecting lens is very heavy in particular, the optical base is liable to strain. And there has been a problem such that the convergence of each liquid crystal panel is liable to deviate because the liquid crystal panels are mounted on the optical base.
Further, when such liquid crystal projectors come to appear on the market and are actually used, the crystal panels and the polarizing plates have to be frequently replaced for the purpose of repair. In case of liquid crystal panels and others installed by a soldering method or the like, it is difficult to replace these liquid crystal panels and polarizing plates. Further, after replacement of these liquid crystal panels and polarizing plates, it is not easy to adjust the convergence of three liquid crystal panels of red liquid crystal panel, green liquid crystal panel and blue liquid crystal panel. Accordingly, when repairing or replacing the liquid crystal panels and polarizing plates, it is necessary to return the main body of the liquid crystal projector to the factory provided with manufacturing equipment. Thus, the users who purchase such liquid crystal projectors have to spend a lot of time for repair or replacement of these parts.
A liquid crystal display video projector of the present invention comprises:
(a) a lamp which emits light;
(b) a color separating means to separate the light into red light, blue light and green light;
(c) a plurality of liquid crystal panels to modulate each color light of the red light, the blue light and the green light,
wherein the plurality of liquid crystal panels include
a first liquid crystal panel to modulate the red light to a first picture element light;
a second liquid crystal panel to modulate the blue light to a second picture element light; and
a third liquid crystal panel to modulate the green light to a third picture element light;
(d) a polarizing plate disposed on at least one of the entrance and exit sides of each liquid crystal panel;
(e) a color synthesizing optical means to synthesize the modulated first picture element light, the second picture element light and the third picture element light into color picture image light;
(f) a projecting lens to project the synthesized color picture image light;
(g) an optical base which retains the plurality of liquid crystal panels, the polarizing plate, the color synthesizing optical means, and the projecting lens; and
(h) a main body case which accommodates the plurality of liquid crystal panels, the polarizing plate, the color separating means, the color synthesizing optical means, the optical base, and the projecting lens,
wherein the color synthesizing optical means includes an X prism, a bonding base, and a panel adjusting member;
the X prism synthesizes the first picture element light, the second picture element light, and the third picture element light;
the bonding base includes an upper bonding base and a lower bonding base, the upper bonding base is disposed above the X prism, and the lower bonding base is disposed under the X prism;
the panel adjusting member includes a first panel adjusting member to install the first liquid crystal panel, a second panel adjusting member to install the second liquid crystal panel, and a third panel adjusting member to install the third liquid crystal panel; and
the color synthesizing optical means and the projecting lens are integrally retained by the optical base in generally parallel relation with the optical axis of the projecting lens.
Preferably, the color synthesizing optical means further includes a panel installing member.
A method of repairing a liquid crystal display video projector of the present invention comprises the configuration of the liquid crystal display video projector described above, and a method of repairing the liquid crystal display video projector comprises the steps of:
(a) removing an optical block including the projecting lens and the color synthesizing optical means from the case;
(b) at least one step of
(i) separating the panel installing member from the panel adjusting member, and removing at least one of the plurality of liquid crystal panels and the polarizing plate from the panel installing member; and
(ii) adjusting the position of each liquid crystal panel by moving the panel installing member via the panel adjusting member.
By the above configuration, even when shocks are given to the projector body, displacement (deflection) of the projecting lens and X prism can be prevented. Further, deviation of the convergence can be prevented with respect to the three liquid crystal panels. Also, a color synthesizing unit including a projecting lens and liquid crystal panel can be retained by a simple structure. In addition, it is very easy to repair.